University of Zagreb, Faculty of Agriculture, Zagreb, Croatia.
University of Zagreb, Faculty of Agriculture, Zagreb, Croatia.
Sci Total Environ. 2019 Mar 25;658:1559-1573. doi: 10.1016/j.scitotenv.2018.12.243. Epub 2018 Dec 21.
The biogeochemistry of soil organic matter (SOM), as a highly complex and dynamic soil property, is of vital importance for the health and ecological functioning of ecosystems, including managed and natural ones. Dominantly composed of carbon (C), SOM functions in global C cycling, including C sequestration and emission (e.g. soil respiration). Mediterranean agroecosystems especially, due to favourable climate conditions for mineralisation of SOM, are expected to go through enhanced SOM decomposition (i.e. C emission) under the ongoing global warming and related climatic change and variability (frequent heat waves, fires and extreme water disturbances). The relatively stable (humified) SOM components, especially in the organically-enriched topsoil layers, due to their specific physical chemistry (strongly charged interface) may have a significant role in biogeochemistry of charged (in)organic nutrients and/or contaminants such as toxic metal ions and persistent organic pollutants. The recent studies show that some natural vulnerabilities of Mediterranean regions (such as high risk of the erosion-driven processes) can increase movement of some hazardous pedospheric constituents (e.g. pesticides) to water bodies and/or into the air, thus influencing the whole ecosystem health. A majority of recent surveys confirm depletion of SOM and spatially variable distribution of metal contamination in the Mediterranean topsoils. Using the advanced geochemical prediction approaches in combination with the relevant soil databases, we characterised organo-mineral and organo-metal complexation and its effect on speciation and sorption of trace metals in karstified Mediterranean agroecosystems. Metal biogeochemistry was found to vary markedly under relatively constant pedosphere conditions, depending on organo-mineral soil components and pH, which may significantly impact metal mobility/availability in the soil-plant continuum. The knowledge of the SOM spatial distribution and dynamics and its interactions with other pedovariables is essential for sustainable management of SOM and control of contaminant mobility to avoid degradation processes in (agro)ecosystems.
土壤有机质（SOM）的生物地球化学，作为一种高度复杂和动态的土壤特性，对于包括管理和自然生态系统的健康和生态功能至关重要。SOM 主要由碳（C）组成，在全球碳循环中发挥作用，包括碳的固存和排放（例如土壤呼吸）。特别是地中海农业生态系统，由于有利于 SOM 的矿化气候条件，预计在当前全球变暖和相关的气候变化和变异性（频繁的热浪、火灾和极端水干扰）下，SOM 会经历增强的分解（即 C 排放）。由于具有特定的物理化学性质（强烈带电的界面），相对稳定的（腐殖化的）SOM 组分，特别是在有机丰富的表土层中，可能在带电（无机）养分和/或污染物（如有毒金属离子和持久性有机污染物）的生物地球化学中发挥重要作用。最近的研究表明，地中海地区的一些自然脆弱性（例如侵蚀驱动过程的高风险）可能会增加一些危险的土壤成分（例如农药）向水体和/或空气中的迁移，从而影响整个生态系统的健康。最近的大多数调查证实，地中海表层土壤中的 SOM 耗竭和金属污染的空间变异性。我们使用先进的地球化学预测方法，结合相关的土壤数据库，研究了岩溶地中海农业生态系统中有机-矿物和有机-金属络合及其对痕量金属形态和吸附的影响。发现金属生物地球化学在相对恒定的土壤圈条件下变化显著，取决于有机-矿物土壤成分和 pH 值，这可能会显著影响土壤-植物连续体中金属的迁移/可用性。了解 SOM 的空间分布和动态及其与其他土壤变量的相互作用，对于 SOM 的可持续管理和控制污染物的迁移以避免（农业）生态系统的退化过程至关重要。
